Getting married doesn't affect your credit score per se. The major credit reporting agencies, for instance, don't combine your credit history with your significant other's once you say "I do."

But, if you have a spouse or soon-to-be-spouse whose credit is less than stellar — or downright "horrible" like John Rampton's wife Kristy's was before they married— prepare yourself for the possibility of losing a few notches in your credit-score belt if you want to help dig him or her out of debt.

First, let's learn more about John and Kristy (who both agreed to share their story): when they got married a couple of years ago, John, 31, knew going in that she had some credit issues.

"I knew she'd had some financial problems — she'd lost her job this and had hard times that — but you never really know until you know," he said. "I just figured, hey, we'll get married, we'll have a few bumps … I know she'll be a little in debt, but we'll just pay it off and we'll go."

"I knew she had an outstanding student loan of about $12,000. Now, if it had been like $100,000 in credit card debt from a shopping habit, that would've been a completely different story, but I wasn't too worried about it," he said.

It wasn't until after they married that they really started talking in earnest about her credit situation, and the reality was she'd had some major financial setbacks. Kristy, now 33, had lost her job and hadn't been able to make her car payments. The vehicle had been repossessed. She'd missed some student loan payments and some credit card payments, too. Her credit score, somewhere in the 400s, according to John, meant she couldn't qualify to get the utilities in her own name.

Lay Out an Action Plan

So, John came up with a plan.

"I took over all finances and gave my wife a monthly allowance to teach her money management," he said.

Then they started pulling Kristy's credit reports. That was helpful because they found a few unpaid medical bills that Kristy hadn't even been aware of, including a $24 bill that had gone to collections.

"We paid those off. We paid off her credit cards and her student loans," John said. "We went to buy a car and I was thinking, we've done all these things, our credit score is going to be waaaay better."

But it wasn't really, and Kristy didn't qualify for the auto loan, so John co-signed. His credit score took a ding.

"It wasn't a severe blow. It took me down a little bit, but it was helping her credit somewhat," John said. But not enough. So they contacted a credit repair company.

"They started disputing all of these things on her credit report," he said. After a few months, things started getting removed. Her credit score improved, and after about six months, they checked to see if she qualified for a credit card. She didn't, even though she didn't have any debt. So they got a secured credit card with a $5,000 limit.